I would like to apply high mesh details such as wrinkles and pores. Should I apply to the base sculpt or to a lower poly retopology?
You could duplicate your object, sculpt on the copy with Dyntopo, then bake the result on the original object.

Another method is to use the Multiresolution modifier then bake the result on the same object as explained here by PIXXO 3D. It works fine with 2.79, not with my version of 2.8 but it may have improved since.


Subdivide your object a bit. Shade Smooth it. Unwrap it (Smart UV Project for example).





Give it a Multiresolution modifier, click Subdivide 2 or 3 times, sculpt the object.





Create a blank picture, prepare your node setup, make sure that the Image Texture is set to Non-Color Data.





Bake the normals.





Deactivate the Multires modifier. Check the result.